Fuel Injector Coupler Gap Valve for Injection Consistency
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Solution Overview
Problem
Current fuel injectors with hydraulic couplers face challenges in maintaining consistent hydraulic fluid filling in the coupler gap space, leading to reduced injection quantity and potential complete absence of injections due to leakage and pressure limitations, especially with increased injection frequency.
Innovation Solution
A one-piece, elastic axially slotted sleeve or leaf spring valve is introduced at the connection between the filling channel and coupler gap space, which opens towards the coupler gap space, ensuring improved refilling and maintaining pressure stability by sealing the filling channel effectively and allowing rapid refilling during injection pauses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the filling channel is closed when the coupler piston moves downwards, then the coupler gap space is continuously filled with hydraulic fluid to compensate for leaks, but the refilling speed is insufficient when multiple injections are made with short intervals, leading to complete absence of desired injections
Solution Approach 1:
The filling channel is designed to dynamically switch between open and closed states based on injection phase. During injection pauses, the channel opens to allow rapid refilling; during active injection, it closes to maintain pressure. This dynamic adaptation resolves the contradiction between refilling speed and injection consistency.
Solution Approach 2:
The system performs preliminary refilling of the coupler gap space during injection pauses before the next injection cycle begins. This ensures that the hydraulic fluid is already in place and pressurized when needed, preventing injection failure due to insufficient filling time.
2Productivity
If a large number of injections are made with short intervals, then injection frequency increases for low emissions, but the coupler gap is emptied more than it is filled again, leading to complete absence of desired injections
Solution Approach 1:
The filling channel remains open during injection pauses to continuously refill the coupler gap space, ensuring that hydraulic fluid volume is maintained even during high-frequency injection cycles. This continuous action prevents the coupler gap from being completely emptied between injections.
Solution Approach 2:
Refilling occurs preliminarily during the pause between injections, preparing the hydraulic system for the next injection event. This advance refilling ensures sufficient fluid volume is available before the next high-speed injection sequence begins.
3Speed
If the filling channel is kept open for rapid refilling, then refilling speed improves, but pressure stability decreases during injection
Solution Approach 1:
The filling channel's open/closed state dynamically adapts to injection phase requirements. During pauses, it opens for rapid refilling; during active injection, it closes to maintain pressure stability. This temporal separation of functions resolves the contradiction between refilling speed and pressure stability.
Solution Approach 2:
The filling channel operates periodically - open during injection pauses for refilling, closed during active injection for pressure maintenance. This periodic switching allows the system to achieve both rapid refilling when needed and pressure stability during injection events.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution significantly enhances the speed stability of the coupler, maintaining a quasi-constant function and preventing pressure limitations, ensuring consistent injection performance even with high-frequency injections.
Implementation Method 1
with each switching operation, a significantly higher pressure than in the surrounding low-pressure space is created in the coupler
Implementation Method 2
a one-piece and elastic valve is arranged which opens in the direction of the coupler gap space
Implementation Method 3
the pressure in the low-pressure space is greater than in the coupler gap space, which is why the leaf spring valve is pushed away from the inner wall of the coupler body
Data Source
Figure 1
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AI summary
The invention relates to a fuel injector 1 of a fuel injection system of an internal combustion engine, wherein the fuel injector 1 has a hydraulic coupler 25 comprising a coupler piston 27 movable in a coupler body 33 and a working piston 28, also movable in the coupler body 33 and coupled thereto via a coupler gap chamber 29, and wherein the coupler gap chamber 29 is connected via at least one filling channel 41 to a low-pressure chamber 22 arranged outside the coupler body 33. According to the invention, a fuel injector 1 with a coupler 25 is provided in which the filling of a coupler gap chamber 29 with high-pressure fluid is improved. This is achieved by arranging a one-piece, elastically deformable valve, opening towards the coupler gap chamber 29, in the region of a connection between the filling channel 41 and the coupler gap chamber 29. This valve is designed as a leaf spring valve 42.